readline: get rid of raw_input code in _setup

pyrepl/readline.py

@@ -407,9 +407,8 @@ def stub(*args, **kwds):
 
 
 def _setup():
-    # TODO: is the raw_input logic still required?
-    global _old_raw_input
-    if _old_raw_input is not None:
+    global _setup_run
+    if _setup_run:
         return
     # don't run _setup twice
 
@@ -425,33 +424,6 @@ def _setup():
     _wrapper.f_out = f_out
     _wrapper.setup_std_streams(sys.stdin, sys.stdout, sys.stderr)
 
-    if "__pypy__" in sys.builtin_module_names:  # PyPy
 
-        def _old_raw_input(prompt=""):
-            # sys.__raw_input__() is only called when stdin and stdout are
-            # as expected and are ttys.  If it is the case, then get_reader()
-            # should not really fail in _wrapper.raw_input().  If it still
-            # does, then we will just cancel the redirection and call again
-            # the built-in raw_input().
-            with contextlib.suppress(AttributeError):
-                del sys.__raw_input__
-            return input(prompt)
-
-        sys.__raw_input__ = _wrapper.raw_input
-
-    else:
-        # this is not really what readline.c does.  Better than nothing I guess
-        try:
-            import builtins
-
-            _old_raw_input = builtins.raw_input
-            builtins.raw_input = _wrapper.raw_input
-        except ImportError:
-            import builtins
-
-            _old_raw_input = builtins.input
-            builtins.input = _wrapper.raw_input
-
-
-_old_raw_input = None
+_setup_run = False
 _setup()